CHEAPEST way to go digital HELP NEEDED

Licence free two-way radio services that now includes both FM and digital channels. Discuss models, modifications and other similar worldwide standards such as FRS and GMRS.
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Re: CHEAPEST way to go digital HELP NEEDED

Postby paulears » 03 Jan 2017, 17:31

I guess we just need to wait until somebody does some proper tests with the right test gear to find out what is happening.

We have similar issues with some of the Chinese lighting equipment I use when they deviate slightly from the DMX protocol, and unusual and quite weird things happen for no apparent reason - in most cases it's timing accuracy for the packets. Some of these needed replacement chips to cure the problem, but a few were sorted with firmware revisions. Not sure if it was ever tracked down to poor coding, or proper instability - I doubt Baofeng will be very transparent on this one.

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Re: CHEAPEST way to go digital HELP NEEDED

Postby radiosification » 05 Jan 2017, 17:10

paulears wrote:Take the point on dPMR, but radar with high PRR has been around for a long time, so certainly possible to switch extremely fast nowadays.

I guess you're referring to being able to switch on and off the PA fast enough here for TDMA. It's possible yes, but it's probably not cheap to do and I think that's why the decided to leave it out of these certain DMR radios.
paulears wrote:So do all DMR portables sync themselves to incoming RF? This suggests that repeaters need to be transmitting continuously, or at least regularly. So each radio sync up with the incoming data ready for TX in the right time slot. I used the term format to refer to the data packet format - bursts and frames. I'm familiar with the format of data streams. In DMR the guard bands are very small as a percentage of the total time for each packet - not surprising clashes happen.

So is the problem really sloppy timing or something more complicated. Sync lockup could be a firmware tweak, hopefully.

They do sync to the repeater before transmitting, yes. Essentially what happens is if a radio user wants to talk the radio will listen to the repeater first to get the correct timing to transmit in the slot it's programmed to. If the repeater is not transmitting already, the radio will ping it to get it to transmit and then it will sync up before transmitting voice.

The problem with these radios is not timing at all. It's just that the PA doesn't turn on and off fast enough. Basically if they tried to turn the PA off for the other timeslot it would still be mostly on by the time the radio wanted to transmit again in its own timeslot. Which means it is transmitting over the other timeslot and blocking it. I guess instead of attempting and failing to turn it off between transmitting in a timeslot, they decided to just leave it on. It could only be solved by rebuilding the radio with a better PA and then modifying the firmware to get it to turn the PA on and off. Not something the consumer could really do, and not something the manufacturer will do either. The best option is just to buy a different radio in the first place.
If you're interested in digital voice, check out my YouTube channel:
http://www.youtube.com/radiosification

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Re: CHEAPEST way to go digital HELP NEEDED

Postby paulears » 06 Jan 2017, 18:45

That's useful, thanks - it does seem that building on a design flaw is never going to be a possible modification if the entire transmit chain is incapable of doing this, and just idling in the 'wrong' data slot. I wonder if they simply use the same PA module that FDMA radios use? Kenwood have been trying to sell me some of their NXDN kit that has been tweaked to operate on dPMR too, but they won't confirm that both formats are able to be used in different channels. Their advertising is a bit blurry in places.

It will be interesting to see if this baofeng radio ever gets sold in a Tier II capable form, won't it?

Thanks
Paul

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Re: CHEAPEST way to go digital HELP NEEDED

Postby troffasky » 06 Jan 2017, 22:16

Looks like it's based on hr_c3000f DMR chip:

http://www.hamradio.cc/forum/index.php?t=msg&goto=3232
[note the AT1846S for the analogue side, presumably a clone of the RDA1846S]

Very little on Google about this, however Baidu yields more hits:

http://www.baidu.com/s?wd=hr-c3000f%20dmr

and we find this:

http://www.qy6.com/qyml/showp13175880.html
[you'll have to stick it into Google Translate]

which is a company selling modules based around DMR ICs. Now obviously it may lose something in translation, but what I read from that page is that the basic model they sell uses the HR_C3000 and the more advanced one uses the HR_C5000. A quick Google for "HR_C5000" shows that it's used in the MD-380! Note that on the qy6 link, the blurb for the advanced module specifically mentions TDMA, but the blurb for the basic one does not.

Nothing on the manufacturer's site about C5000, only C3000:

http://www.hongruitech.com.cn/index.php ... /cid/8/s/3

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Re: CHEAPEST way to go digital HELP NEEDED

Postby Farty » 07 Jan 2017, 11:49

WARLOCK wrote:Is there a cheap way to get onto digital radio ,these days ???


Yes, join the police and get given one.

Or steal one.

Neither is really recommended though.
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Re: CHEAPEST way to go digital HELP NEEDED

Postby radiosification » 07 Jan 2017, 22:08

paulears wrote:It will be interesting to see if this baofeng radio ever gets sold in a Tier II capable form, won't it?

It already is (mis)sold as a tier 2 radio. Check out the DM-5R plus

Farty wrote:
WARLOCK wrote:Is there a cheap way to get onto digital radio ,these days ???


Yes, join the police and get given one.

That isn't cheap at all. You have to do a degree to get in these days!

Troffasky, some good info there!
If you're interested in digital voice, check out my YouTube channel:
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Re: CHEAPEST way to go digital HELP NEEDED

Postby Admiral » 08 Jan 2017, 08:37

It was always anticipated that after a couple of years and the R&D and tooling costs were covered that the price of an MD380/RT3 would settle at around £59 retail. That's still a few months away, currently they can be had for £75 with cable.

http://www.ebay.co.uk/itm/like/36162438 ... 085&crdt=0
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Re: CHEAPEST way to go digital HELP NEEDED

Postby gmham » 08 Jan 2017, 10:59

£55 for the zastone D900 clone before Xmas on amazon so yes they certainly are coming down in price. Even at the current £75 I still think they are a good buy . the build quality seems very good indeed.
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Re: CHEAPEST way to go digital HELP NEEDED

Postby radiosification » 14 Feb 2017, 17:04

radiosification wrote:
FakeJake wrote:It does do tier 2, heard someone on UK wide using one via his local repeater. It may still be transmitting on both slots though, I suspect. Needs further testing.

https://www.youtube.com/watch?v=BQkzq0H ... nel=spymsn
As you can see in this video, it transmits on both timeslots therefore it's not a proper tier 2 radio. It isn't even a proper DMR radio to be honest because even tier 1 radios are supposed to transmit in only one slot and not both. It never should have been sold as a DMR radio.

I want to make a correction to my post quoted above.
I was reading the ETSI DMR standards documents recently and they actually say something about continuous transmission mode being allowed on tier 1 DMR radios, so actually it looks like I was incorrect about this. I believe that tier 1 DMR radios are allowed to not do TDMA.

However, the DM-5R still does not meet the specification for DMR tier 1, since it does not have a limited power output, is not limited to PMR446, does not have a fixed (non removable) antenna. These factors combined mean that a tier 1 radio not being able to do TDMA is not really a problem because it would never be trying to transmit on a repeater input anyway while it is operating in the 446 MHz license free band.

The Baofeng DM-5R is still not a tier 1 radio or a tier 2 radio. It is best described as a "simplex only DMR radio". I made a video yesterday trying to explain the radio properly which you can see here (https://youtu.be/m14v6h2h_B0) if you are interested.
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Re: CHEAPEST way to go digital HELP NEEDED

Postby paulears » 14 Feb 2017, 21:23

The problem really is that Tier 1 has been hijacked and is now being sold into the unlicensed bands. The cynic in me wonders if this is simply because of the problems Tier 1 causes in Tier 2 worlds - in the way we've been talking. The DMR association points Tier 1 DMR to the 446 band, but the older ETSI documentation didn't. I'm looking to see if I can work out when they moved their emphasis towards unlicensed. I note now that many manufacturers now have their digital products segregated into licensed and unlicensed, and that was not there when I started my foray into digital.

Are the gateposts moving?

The actual standards - available on the ETSI site still say
1 Scope
The present document contains technical requirements for Digital Mobile Radio (DMR) operating in the existing licensed land mobile service frequency bands, as identified in CEPT/ERC/T/R 25-08 [i.1].
The present document describes the voice and generic services and facilities of a scalable Digital Mobile Radio system which covers three tiers of possible products:
Tier I: Tier II: Tier III:
DMR equipment having an integral antenna and working in direct mode (communication without infrastructure) under a general authorization with no individual rights operation.
DMR systems operating under individual licences working in direct mode (unit-to-unit) or using a Base Station (BS) for repeating.
DMR trunking systems under individual licences operating with a controller function that automatically regulates the communications.
9 ETSI TS 102 361-2 V2.3.1 (2016-02)
NOTE1: TierIIandTierIIIproductsencompassbothsimulcastandnon-simulcastsystems.
NOTE2: Thethreetiersofpossibleproductswillworkonlyindependentlyandnotinteroperable.
The present document specifies the voice and generic services and facilities of DMR that has been specifically developed with the intention of being suitable for all identified product tiers. The DMR protocol is intended to be applicable to the land mobile frequency bands, physical channel offset, duplex spacing, range assumptions and all other spectrum parameters without need for any change.

Note the last bit - the protocols are intended for the land mobile bands. It seems the Digital Mobile Association, not ETSI, are the ones talking about PRM446. I think we need to consider who is making these 'rules' up? I suspect the manufacturers.

It's interesting to see that all the kenwood UK DMR radios are Tier 2 apart from their PMR446 ones, which are currently not matched with the rest of Kenwood's global business. It's good to see both Nexedge (which is the small system I'm running) and DMR in the line-up, but that Baofeng does appear to meet the Tier 1 DMR specification. As such, it would appear to be perfectly licensable with the current OFCOM system, as the ETSI spec seems the key to approvals, along with the others from P25 land, Motorola and Kenwood's Nexedge. I can't find any reason why somebody running an analogue 12.5KHz system couldn't just replace their radios with Tier digital if they only use simplex - or just use a duplex frequency split. I don't think there are any Tier 1 repeaters, but that wouldn't seem to be against the rules? DMR Tier 2 is the usual digital solution but if you didn't want all those advantages TDMA offers, it should be possible.

Has anyone tried simply repeating digital on an analogue system? my quick tests a few months ago suggested it did work if the discriminator broadband output is fed to the transmitter? Test time, if I get a chance.

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Re: CHEAPEST way to go digital HELP NEEDED

Postby radiosification » 14 Feb 2017, 22:36

Tier 1 is meant for license free. Maybe it wasn't originally in the ETSI specification, but then again, the ETSI documents don't really say very much about tier 1. My view on it is that we may as well assume that the information that "tier 1 is for PMR446" is correct, especially if it is from a source like the DMR association. Surely the DMR association know what they're talking about, right?

I don't think that tier 1 was designed for simplex use in any old band because that causes many other issues.
Firstly what would be the point in using a 12.5 KHz digital standard for simplex use, when this standard was meant for TDMA use. It would make a lot more sense to use either:
A) A 6.25KHz digital standard like dPMR, or B) A 12.5KHz digital standard that actually makes use of the whole channel i.e P25. Because if you're going to use all that spectrum for only one conversation you may as well use a full rate vocoder (as P25 does) and have better sounding audio.
Secondly because simplex operation is included in the tier 2 and 3 standard with support for 6.25e direct mode, which makes use of TDMA to provide two conversations simultaneously on a 12.5KHz simplex channel. This is far superior to tier 1. Anyone who wanted to use direct mode (simplex) on a licensed frequency (by the logic that they're paying for capacity and would want to make the best use of it) would surely either pick this, or something else as I described in options A and B over a wasteful option like tier 1's continuous transmission.

Maybe by "under a general authorization with no individual rights operation" they were actually referring to using this in a license free setup, just without specifying the band so that it could be adopted in other countries? I don't really know what else they could mean with this phrase, all I know is that it's very unclear. Here is an interesting discussion from many years ago (2005, so 12 years ago!) on radioreference. They couldn't seem to figure out what it meant either. http://forums.radioreference.com/genera ... ation.html
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Re: CHEAPEST way to go digital HELP NEEDED

Postby paulears » 15 Feb 2017, 09:44

I know what you mean, but you really can;t say you are the only person who knows when clearly, you're having to make assumptions based on common sense. ETSI invented the protocol, and developed the specification. They make no distinction on VHF or UHF, and make no mention at all of any territory or license restrictions. The Organisation the UK setup to be the centre of all things digital radio have developed this idea of Tier 1 becoming license free, when clearly Tier 1 became an annoyance to users wanting more advanced features and the increased capacity. In the early documentation the thing that has now happened with the Boafeng was not talked about. As in Tier 1 DMR is actually pretty useless. I notice Tait have some updated info,
Tier I (unlicensed): DMR equipment works in Direct Mode (unit-to-unit) on public frequencies. Tier 1 DMR devices are best for individuals, recreation, small retail, or other situations that do not require wide area coverage.

They quote the DMR Association's interpretation of ETSI's spec, not the actual wording of the spec.

I wonder if Baofeng just got the spec, saw Tier 1 as at the basic version and they built a radio to meet it without any thought about co-existence with Tier 2 kit. Have you also noticed that Tier 2 is now being talked about as radio to radio, not just repeaters. This too has changed in what? 18 months? The original advice from the people selling radios was that Tier 1 was radio to radio, Tier 2 was for repeaters and Tier 3 was trunked. Now the goal posts have moved with the sensible advice of the DMR Association who clearly understand the problem that has just 'appeared'. The ham use doesn't count because using Tier 1 is not against anyone's license terms, but wrecks Tier 2 access to the networks.

I strongly believe that the firm pointing of Tier 1 to unlicensed spectrum just solves the problem.

I'm not so sure on the typical license holders interest in the one or two channel sharing a channel. They could use pDMR and run two in their channel allocation, or use TDMA and do the same thing. Schools, as an example, have bought digital radios to solve their personal data issues, but some of these also have a license - so could run a cheaper system on Tier 1 using branded guaranteed products - but these are no longer available in the UK, only on PMR446 - which is a bit crazy. why would you spend a lot of money on a digital radio and then use it in a very unregulated band where people can accidentally prevent your system working properly? Madness.

I don't understand why they would restrict usage by having Tier 1 kit, but only in a very small band. Just weird marketing.

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Re: CHEAPEST way to go digital HELP NEEDED

Postby radiosification » 15 Feb 2017, 10:40

Well as I say, tier 2 does everything tier 1 does and more, so anyone who wants to use a DMR radio in simplex can just buy a tier 2 radio. I don't think there were ever any tier 1 radios made to work outside of the PMR446 band.
Was the dPMR standard made before DMR? In that standard they also had a separate bit for license free (dPMR446) although their naming is a lot better.

I guess we'll have to agree to disagree on this point. I say that Tier 1 DMR is only for license free use. You say that ETSI did not intend for it to be only for license free. Whichever it is, at least we can agree that tier 2 is a much better choice for use in licensed bands.
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Re: CHEAPEST way to go digital HELP NEEDED

Postby paulears » 15 Feb 2017, 20:31

Absolutely! The current labelling of DMR Tier 1 for PMR446 is kind of a cop out dumping ground for radios with little sophistication, and I guess they're not going to be around long - too expensive for something that doesn't do much!

The current advice to use Tier 1 in only unlicensed bands worldwide is a neat solution to the problems the damn things cause in Tier 2 and 3 territory.

Oh - I did try the repeater pass though thing this afternoon. I can confirm that Neither TYT or Kenwood repeaters will pass digital signals - although the 'sound' of their output appears to be the same - I tried DMR Tier 2 in repeater mode and back to back mode on 380s, dPMR on Anysecu and Kirisun (S760s) and Kenwood NXDN - none functioned through the repeaters. Didn't really expect it, but at least confirmed it now for certain.

I had some issues with programming the DMR 380s to use repeater talk around. No amount of programming different solutions - as in the talk around tick box, or just setting reverse frequencies worked, and I'm not quite sure why? The Nexedge Kenwood's I have I've not put the new DMR firmware in yet because frankly I daren't- yet. At some point I'll perhaps give it a go - if the version number I have is compatible. Kenwood referred me to a dealer, which didn't help too much.


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